Winching apparatus

ABSTRACT

A winching arrangement is disclosed for winching a cable comprising a winching frame; a capstan ( 11 ) for winding the cable onto; a drive motor ( 3 ) for driving the capstan; and a first clutch mechanism for disengaging the capstan from the clutch when the torsional load on the cable exceeds a first predetermined limit. Preferably, the first clutch mechanism ( 6 ) is located within the capstan and ideally the clutch mechanism is an adjustable cone clutch mechanism. The winching arrangement can further include a second adjustable clutch mechanism located adjacent the motor for providing secondary disengagement of the motor from the capstan when the cable exceeds a second predetermined limit. Further, a gear reducer ( 8 ) can be interconnected between the capstan and the drive motor. Preferably, the arrangement also includes a fixing arm ( 15, 18 ) for fixing the winch to an object wherein the cable, the capstan and the fixing arm are aligned substantially concentrically during operation.

FIELD OF THE INVENTION

The present invention relates to the field of winching systems and inparticular, discloses an improved form of winch especially useful forwinching cables such as optical fibre communication cables, data cables,power cables, ropes for hauling etc.

BACKGROUND OF THE INVENTION

There are obviously many uses for winching systems in society. Oneparticular popular use of a winching system is the winching of cablessuch as optical fibre cables or the like through conduits by workmen inlaying down cable systems. Presently, known techniques rely upon a motorsystem and geared arrangement for driving a capstan around which a cableor lead wire is wrapped. The capstan is then driven by the motor so asto rotate and thereby wind on the cable wire in the usual manner.

Unfortunately, presently utilised systems have a number ofdisadvantages. In particular, the presently utilised systems have beenfound to be excessively dangerous in that a wire, under tension isdriven by a motor device. Minimal control is placed over the system andhence, as a result of overstressing of equipment, the wire and/orequipment can malfunction which can result in severe bodily injury topersons operating the equipment. Another common problem is overstressingof a cable when too much tension is applied to the cable. The effectsapplied to a cable through overstressing may in turn cause it tomalfunction or to be a of a poor quality. Further, known arrangementsfor winching of the cables can be excessively dangerous due toimbalances and variations in the forces created by the winchingarrangement when driving a cable system.

SUMMARY OF THE INVENTION

It is therefore evident that there is a long felt need for a cablehauling system which provides for a safer, more effective operation.

In accordance with a first aspect of the present invention, there isprovided a winching arrangement for winching a cable comprising awinching frame; a capstan for winding the cable onto; a drive motor fordriving the capstan; and a first mechanical torque limiting mechanismfor disengaging the capstan from the drive motor when the torsional loadon the capstan exceeds a first predetermined limit.

Preferably, the mechanical torque limiting mechanism comprises a clutchmechanism which is located within the capstan. Ideally, a cone clutchmechanism is used.

Further, their is preferably also provided a second mechanical torquelimiting mechanism located adjacent the motor for providing secondarydisengagement of the motor from the capstan when the load on the capstanexceeds a second predetermined limit and a gear reducer connectedbetween the capstan and the drive motor.

The winching arrangement as can further include a fixing arm for fixingthe winch to an object wherein the cable, the capstan and the fixing armare aligned substantially concentrically during operation and a capstansupport means interconnecting the capstan with a winching frame whereinnon torsional forces on the capstan are communicated by the capstansupport means to the frame. The capstan support means is preferablyinterconnected to the frame substantially concentrically with the cable,capstan and fixing arm and the fixing arm is pivotally mounted to thewinching frame.

Ideally, the cone clutch is adjustable so as to set the firstpredetermined limit and located inside the capstan in a sealedtamperproof manner.

In accordance with a second aspect of the present invention, there isprovided in a winching arrangement for winching a cable comprising awinching frame; a capstan for winding the cable onto; and a drive motorfor driving the capstan, the drive motor driving having a number ofactive setting and the drive motor only driving the capstan at apredetermined number of the settings; a method of driving the capstancomprising the steps of: activating the drive motor and setting themotor to a non-driving setting; loading the cable on the capstan forhaulage by the winching arrangement; setting the drive motor to adriving setting so as to haul the cable.

In one embodiment the number of capstan support means is two. Theinvention can further include a third mechanical torque limiting devicewhich includes a latching mechanism actuated when the torsional loadexceeds a third predetermined limit, the actuation being by a springloaded strike pin which activates a switch which disables the drivemotor.

In one arrangement the capstan includes an internal gear reducer unitfor providing a gear reduction driving of the capstan and the capstan isliquid cooled.

In a further modification the arrangement can include a strain gauge formeasuring the torsional load on the winching apparatus.

Advantageously, an external roll cage is provided of facilitatingconvenient and safe operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of thepresent invention, preferred forms of the invention will now bedescribed, by way of example only, with reference to the accompanyingdrawings in which:

FIG. 1 illustrates a top schematic plan view of the preferredembodiment;

FIG. 2 illustrates a side schematic plan view of the preferredembodiment;

FIG. 3 is an enlarged view of the capstan and mechanical tensionlimiter;

FIG. 4 illustrates a top plan view of a modified embodiment including amechanical tension limiter;

FIG. 5 is a schematic side plan view of a modified embodiment includinga mechanical tension limiter;

FIG. 6 is a top plan view of a further modified embodiment includingdual support arms;

FIG. 7 is a side plan view of the modified embodiment of FIG. 6 furtherillustrating a wind up drum;

FIG. 8 is an exploded plan view of the core capstan arrangement and mainshaft;

FIG. 9 is an end plan view of a portion of the arrangement of FIG. 8;

FIG. 10 illustrates an exploded plan view of a modified dual cone clutcharrangement suitable for use in an embodiment of the invention;

FIG. 11 illustrates a water cooled cone clutch arrangement suitable forhandling the heavy duty loads in an embodiment;

FIG. 12 illustrates a water cooled clutch mechanism including dual mainshafts;

FIG. 13 is an exploded plan view of the arrangement of FIG. 12;

FIG. 14 illustrates the cylinder supporting strut of the preferredembodiment;

FIG. 15 is an exploded plan view of the cylinder supporting strut andmechanical tension limiter used in a modified embodiment;

FIG. 16 illustrates a supporting strut and cylinder having an enlargedcapstan carrying capability;

FIG. 17 illustrates the supporting struts of a dual cylinderarrangement;

FIG. 18 is an exploded plan view illustrating the mechanical tensionlimiter;

FIG. 19 is an exploded plan view of the mechanical tension limiter;

FIG. 20 illustrates the firing mechanism of the mechanical tensionlimiter;

FIG. 21 is a further illustration of the mechanical tension limiterfiring mechanism of a modified embodiment;

FIG. 22 is a further illustration of portion of the mechanical tensionlimiter of a modified embodiment;

FIG. 23 illustrates the strain gauge of a modified embodiment;

FIG. 25 is a top plan view of a modified embodiment;

FIG. 26 is a side plan view of a modified embodiment; and

FIG. 27 is a front side view of a modified embodiment.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

In the preferred embodiment, there is provided a winching system havinga capstan with a pre-loaded cone clutch that torque limits the maximumtension or applied force on a rope or cable being hauled. Further, thecapstan is arranged such that the cable is in direct alignment with afixing device for a fixing the winch structure to a substrate or otherobject such as a motor vehicle. Preferably a further torque limiter canalso be provided to set an overall torque limit for the device. Thepreferred embodiment preferably includes a radial bearing interconnectedto a capstan support device which is in turn connected to the winchingframe for transferring any non-torsional forces to the frame or chassisof the winch and in turn to the substrate rather than the drive train ofthe motor.

Turning initially to FIGS. 1 and 2, there are illustrated various planand elevation views of the preferred embodiment 1. The preferredembodiment is mounted on a cage such as 2 and includes a motor drivedevice shown schematically as 3 which is attached to and drives a firstshaft 7. The motor 3 can be preferably be a high end portable petroltype engine acquired in accordance with driving requirements.Preferably, the motor drive 3 is the type which includes a wet clutchmechanism such that the motor drive output is only engaged when enginerevolutions exceed a predetermined limit. Such engines are readilyavailable from several manufacturers, most notably Yamaha. A firstclutch mechanism 6 is provided and acts as a secondary torque limiterwhich preferably has adjustable torque settings. The clutch mechanism 6of the secondary torque limiter can be of a standard type available fromseveral clutch mechanism manufacturers. Preferably, the clutch mechanism6 is provided in a locked cage so that an operational supervisor isassured that a maximum tension will not be exceeded. That is, if othertorque limiting devices fail and the tension on the capstan exceedsspecifications set by the cable manufacturer, the secondary torquelimiter of the clutch mechanism 6 can positively disengage the driveshaft 5 to a gear reducer 8 and thus the capstan. Preferably, the clutchmechanism 6 is of the type where the torque limiter, in disengaging,moves a set distance and a micro switch is actuated which automaticallycuts the motor engine.

The clutch mechanism 6 has a shaft 5 which is in turn connected to agearing system 8 which acts as a gear reducer in accordance withrequirements, thus, the motor 3 can be in a geared relationship to thecapstan.

The output shaft of the gear reducer 8 is interconnected to a capstan11. The capstan 11 includes an internal cone clutch which is designed tooperate to a first predetermined torque loading. The capstan 11 islocated so that any cable pulled is in line with a swing arm 15. In thisway, the preferred embodiment provides for a direct alignment of thetorsional forces with the frame and a fixture which is preferablyattached to the end of the swing arm 15.

In an alternative arrangement, an additional mechanically adjustabletension limiter is provided. This arrangement is illustrated in FIGS. 4and 5 and includes a mechanical tension limiting device 60 that moves aset distance to actuate a microswitch that cuts the motor when the cable4 exceeds a predetermined limit as determined via the reaction arm 80which is secured to a swivelling gear reducer securely located on thewinching frames cylinder 17. FIG. 4 illustrates a top plan view of thisalternative embodiment having a swivelling gear reducer 8 andmechanically adjustable tension limiter 60 with FIG. 5 illustrating aside view thereof. In FIG. 3, there is illustrated an enlarged view ofportions of FIG. 4 including the mechanically adjustable tensionlimiters 60. The operation of the mechanically adjustable tensionlimiter 60 is described hereinafter.

Returning to FIG. 1, in order to avoid any further twisting forces beingplaced upon gear box reducer 8, the capstan 11 includes internal radialbearings interconnecting with a cylinder 17. The cylinder 17 is affixedto the frame via strut 18 and in turn engages the swing arm 15 via pivotmount 19. The cylinder 17 is provided to transfer any non torsionalforces directly to the frame via strut 18.

The chassis frame preferably includes, as illustrated in FIG. 1 and FIG.2, a set of wheels 20 to provide for simplified transport.

Other arrangements are possible for meeting different requirements. Forexample, FIG. 6 illustrates a top plan view and FIG. 7 illustrates aside plan view of an alternative arrangement which includes dualcylinders 17 a, 17 b and corresponding arms 18 a and 18 b and isdesigned for commuting large torsional loads via pivot arm 15 to afixing point. Further, as illustrated in FIG. 7, a drum 21 is designedto take up a cable 22 being winched by the capstan. The cable 22 is fedthrough a feeder mechanism 23 so as to properly align the cable with thesurface of the capstan.

Turning to FIGS. 8 and 9, there is illustrated in FIG. 8 an explodedplan view of the capstan 11 and in FIG. 9 an assembled end view isshown. The outer surface of the capstan 26 preferably includes ahardened chrome serrated finish and engages a cone clutch mechanismformed by inner cone portion 13.

The cone portion 13 is inserted into one end of the outer capstan 26 anda main shaft 40 is inserted inside the cone. The main shaft 40 includesa keyway 41 which engages the output of the gear box arrangement (8 FIG.1). The main shaft 40 is retained in position by means of retainingwasher 42, washer 43 and a socket screw 44. Importantly, a bearing 45 isprovided around main shaft 40, the bearing 45 acting on an internalsurface of the cylinder 17 of FIG. 1 so as to transmit any non-tortionalforces on the main shaft 40 to the frame via the cylinder 17.

A second bearing 46 is inserted into capstan 11 so as to provide for thetransmission of non-torsional forces from the capstan to the main shaft.The setting of the torque limit of the capstan arrangement is providedby means of discs 48 and tab washer 49 which are fixed in position bymeans of lock nut 50. A tamper proof cap 51 is also provided so as tosecure one end of the capstan 11 from tampering.

Of course, other torque limiting clutch arrangements are possible. Forexample, in FIG. 10, there is illustrated an exploded plan view of aperspective dual cone clutch mechanism having a larger capstan 28 forheavier duty operations. The larger capstan is driven by dual conearrangements 13 a and 13 b. The other portions of the arrangement ofFIG. 10 being as previously discussed. Still large arrangements arepossible. For example, in FIG. 11, there is illustrated a still largerdual clutch cone mechanism suitable for utilization in even heaver dutyoperations. The cone clutch mechanism 30 includes its own internallysealed gear reducers 31, 32 in addition to coolant flow chambers 33, 34which pump fluid around the internal cone mechanism. A separate coolantflow unit 36 being provided for pumping cooling fluid around the capstan30. The arrangement of FIG. 11 is particular useful for handling heavyexcessive loads where slipping and hence heating may be prominent. Theenlarged arrangement of FIG. 11 is ideally supported by the Y frameconfigured winches previously discussed with reference to FIG. 6.

FIG. 12 illustrates a further alternative capstan arrangement of FIG. 11extended to include a second shaft 37 having a series of internalcoolant carrying conduits 38. FIG. 13 illustrates an explodedperspective of the arrangement of FIG. 12 showing the components in moredetails.

The utilisation of the cone clutch within the capstan can be set so asto provide for clutch operation only up to a maximum torsional limit. Itwill be therefore evident that the capstans disclosed are designed witha pre-loaded cone clutch where its torque limits the maximumtension/applied force in rope/cable hauled. The second torque limiter 6between the prime mover and gear reducer is set at a slightly highertorque to ensure that the primary torque limiter does not exceedmanufacturers hauling/loading specifications (this also accommodates fordrive train inefficiencies). As shown in FIG. 1, the radial load due tothe rope/cable hauled will take a straight line from centre of thecurved profile on the capstan 11 through to the fasteningfixing/anchoring device 15. This ensures that the force generated by theropes/cables are in line and coupled directly via the frame/chassis withthe fixing/anchoring device which takes up the reaction force. Thus, noexcess turning moment is induced on the system via capstan 11. Theframe/chassis carries tension/applied force via the radial bearings 45,46 to cylinder 17 and transfers applied forces through to the towingtongue/pintel hook or fixing device. Thus the gear reducer 8 onlytransfers pure torsion from the prime mover or motor 3 through theshaft. The gearbox 8 therefore does not carry any overhung loads. Thesafety of the system is also improved by having the gear reducer radialload taken up by a radial bearing installed independently in theframe/chassis and offset from the reducer via the cylinder.

The capstan 11 can be made of a hard faced corrosion and abrasionresistant material having a serrated finish to prolong its working life.

The preferred embodiment has been designed into it to allow for directwinching loads for force or torque, Bi-directional and undirectionalmotion, including overriding and irreversible motion of the capstan.

The maximum force to be applied to a cable/rope is set/calibrated on thetorque limited capstan 11. The capstan is a primary torque limitingdevice that ensures application forces are not exceeded. The capstanobviously slips when the applied force/tension in the rope exceeds themaximum tension the torque limited capstan is calibrated at. An enclosedsecond torque limiter 6 between the prime mover and the gear reducer,set at a slightly higher torque reading, and in the event of malfunctionof the primary torque limiting device, this second torque limiterdisengages positively and activates a micro switch to stop the primemover 3 and/or raise an alarm. The objective of this process is toensure that tensions in the rope/cable are not exceeded and guaranteethat the characteristics of ropes/cables are maintained as stipulated bythe manufacturer.

As noted previously, the capstan 11 has designed into it a sealed coneclutch that can be preloaded via a resilient disk (belville) washerswhich acts on a bearing to eliminate wear. The preload is maintained onthe cone clutch via the disk washer and bearing locked in position onits shaft with a tab washer 49 and lock nuts 50. The cone clutchmaterial is preferably selected to give long life which allows it to bedinto the capstan bore if any slip occurs. This preloaded capstan can bere-calibrated for checking or new tension settings.

The capstan assembly complete with its keyed shaft is preferably locatedonto a “seal for life” bearing housed in the frame/chassis on one endand a bolted gear reducer 8 concentrically located on the other end ofthe frame/chassis hub via a spigot and flange arrangement.

It is noted previously, alternative embodiments of the present inventioncan also include an additional mechanical tension limiter, the detailsof which are shown in more detail in FIG. 15 which illustrates, in apartially exploded form, the mechanical tension limiter 60 whichinterconnects with a reaction arm 81 which are connected to the cylinder17 by means of plate 82, bearing 83 and bearing retainer 84. The systembeing interconnected intermediate of the cylinder 17 and gear reducer 8.FIG. 18 shows an alternative form of mounting of the mechanical tensionlimiter 60 which again is shown in partially exploded perspective formand interconnects with a reaction arm 81 which is mounted on the gearreducer 8 or on bearing secured to the cylinder 17.

The operation of the additional mechanical tension limiter will bedescribed with reference to FIGS. 19-22 with FIG. 19 illustrated aninitial exploded plan view of the mechanical tension limiter, FIG. 20illustrating a sectional plan view through the line A—A of FIG. 19, FIG.21 illustrating a sectional view through the line B—B of FIG. 20 andFIG. 22 illustrating a section through the line C—C of FIG. 21.

The mechanical latching mechanism releases a spring loaded strike pin 72to actuate a sealed micro switch 69 which automatically stops the primemover when a further predetermined limit is exceeded. The mechanicaltension limiter operation is dictated by the applied force from thereaction arm 81 connected to the swivelling gear reducer positivelylocated on cylinder 17. The applied force translates through the springpillar 64 which compresses the disc washer 66. The edge of the springpillar 64 is set a specified distance relative to the proportionalelastic deflection of the disc washer 66. For example, a 5 kN deflectionis reflected by a 0.5 mm deflection (in compression) of the disc washer66 and spring pillar 64 respectively. The edge of the spring pillar 64lifts the spring loaded main pin 75 and allows the spring loaded strikepin 72 to deflect across the main pin 75 hole to lift the bell crank ofthe limit switch 69 with stops the prime mover. The other micro-switchcan be set at a higher tension to stop the prime mover when thepreferred embodiment malfunctions in accordance with the winchingcode/regulations of the country and state the winching apparatusoperates in.

In a further modification, a strain gauge/load cell as illustrated inFIG. 23 can be connected in series with the mechanical tension limiterto allow a load generated via the strain gauges 92 permanently mountedon the deflection bar 91 to be recorded via amplifier signalconditioning system. The deflection bar is housed in the cover 93, theend plates 94 and held in place by the circlips 95. The signal istransmitted via the coaxial cable 99 to the amplifier signalconditioning system.

Returning to the earlier drawings, the keyed input shaft of the gearreducer 8 locates the secondary torque limiter 6 which has an adjustabletorque settings. If the primary torque limiter tension in the capstan isfouled or exceeds the specification set by the rope/cable manufacturer,the secondary torque limiter positively disengages the input shaft tothe gear reducer and thus also the capstan. Also, as the torque limiterdisengages a location disk moves a set distance, and a micro switch isactuated which automatically stops the prime mover.

Although different forms of motor can be used, the motor 3 is preferablykeyed and connected to the secondary torque limiter clutch 6. The motoris located and anchored on the frame/chassis and concentrically alignedwith the axis of the input shaft to the gear reducer.

Two rope guides 23 can be located around the capstan to assist withcentring the position of the cable/rope and assist the operator duringuse.

An emergency stop button 24 can be located near but above the capstan,visual in a 360° horizontal plane.

The Winch is mounted in a roll cage e.g. 2 to protect it from mechanicaldamage.

The extension arm 15 also allows for an increase in the length of theframe/chassis reducing the lifting effort by the operator. Furthermore,when the winch is stored, the extension arm 15 can be positioned acrossthe front of the engine for convenience and storage.

It will be obvious to those skilled in the art that the operation of thepreferred embodiment has direct application to many different fieldswhere pulling of cables or ropes is required. For example, the followinglist comprises a few of the applications of the present invention whichwill be readily apparent to those skilled in the art.

Communication & Power Hauling cable Rescue & Fire Brigade Rescueoperations and clearing Four wheel driving Pulling the 4WD out of rutsAgriculture Pulling farm equipment, ancillary items out of precariouspositions Fishery Nets & boating Maritime Boats and hazardous/foreignsolids in the water Forestry Logging and equipment ConstructionMaterials and equipment Mining Equipment and pits, ROPS and FOPSoperations Military Applications Water Dredging Ancillary servicesloading and unloading

It can be readily evident that small or large capstans can be utilisedto satisfy the regulations in force in each country.

Further, as an added safety feature, the preferred embodiment isprovided with an emergency stop switch 24 at a centrally located point.

The preferred embodiment provides for a very effective and safe form ofoperation. Through the utilisation of a wet clutch arrangement whichonly engages after a certain level of revolutions have been reached, theengine 3 can be started at a low revolution level so that the main driveshaft is not engaged. Next, the cable to be hauled can be wound aroundcapstan 11. The operator can then step back from the apparatus andseparately increase the engine revolutions so as to engage the mainengine whilst the operator is nowhere near the capstan surface 11. Inthis way, a much safer form of operation of the winching arrangement isprovided.

It will be evident also that further modifications can be provided. Forexample, the strut 18 may contain a strain gage so as to provide anindicator of the stress with which the preferred embodiment operates.

It would be appreciated by a person skilled in the art that numerousvariations and/or modifications may be made to the present invention asshown in the specific embodiments without departing from the spirit orscope of the invention as broadly described. The presently describedembodiments are, therefore, to be considered in all respects to beillustrative and not restrictive.

What is claimed is:
 1. A winching apparatus for winching a cable comprising: (a) a winching frame; (b) a capstan for winding the cable to be winched; (c) a drive motor for driving said capstan; and (d) a first mechanical torque limiting mechanism for limiting the maximum torque on a winching load in operation to a first predetermined limit and for maintaining a substantially constant torque under load at said maximum torque, wherein said first mechanical torque limiting mechanism is located within said capstan.
 2. A winching apparatus as claimed in claim 1 wherein said mechanical torque limiting mechanism comprises a clutch mechanism.
 3. A winching apparatus as claimed in claim 2 wherein said capstan is liquid cooled.
 4. A winching apparatus as claimed in claim 1 wherein said first mechanical torque limiting mechanism comprises a cone clutch mechanism.
 5. A winching apparatus as claimed in claim 4 wherein said cone clutch is adjustable so as to set said first predetermined limit.
 6. A winching apparatus as claimed in claim 1 further comprising: a second mechanical torque limiting mechanism located adjacent said motor for providing secondary disengagement of said motor from said capstan when the load on said capstan exceeds a second predetermined limit.
 7. A winching apparatus as claimed in claim 6 further comprising a third mechanical torque limiting device which includes a latching mechanism actuated when said torsional load exceeds a third predetermined limit, said actuation being by a spring loaded strike pin which activates a switch which disables said driver motor.
 8. A winching apparatus as claimed in claim 1 further comprising a gear reducer connected between said capstan and said drive motor.
 9. A winching apparatus as claimed in claim 1 further comprising a fixing arm for fixing said winch to an object wherein said cable, said capstan, said fixing arm and said object are aligned during operation.
 10. A winching apparatus as claimed in claim 9 wherein said fixing arm is pivotally mounted to said winching frame.
 11. A winching apparatus as claimed in claim 1 further comprising: at least one capstan support means interconnecting said capstan with a winching frame wherein non torsional forces on said capstan are communicated by said capstan support means to said frame.
 12. A winching apparatus as claimed in claim 11 wherein the number of capstan support means is two.
 13. A winching apparatus as claimed in claim 11 wherein the apparatus further comprises a fixing arm for fixing a winch to an object, and wherein said capstan support means is interconnected to said frame in substantial alignment with said cable, capstan and fixing arm.
 14. A winching apparatus as claimed in claim 1 wherein said capstan includes an internal gear reducer unit for providing a great reduction driving of said capstan.
 15. A winching apparatus as claimed in claim 1 further comprising a strain gauge for measuring the torsional load on said winching apparatus.
 16. A winching apparatus as claimed in claim 1 wherein said first mechanism torque limiting mechanical is located inside said capstan in a sealed tamperproof manner.
 17. A winching apparatus as claimed in claim 1 further comprising an external roll cage.
 18. A winching apparatus as claimed in claim 1, wherein said capstan includes on a surface thereof an indicator of the torsional load operational characteristics of said capstan.
 19. A winching apparatus as claimed in claim 18, wherein said indicator comprises a color indicator on the surface of said capstan.
 20. A method of driving a capstan for winding a cable to be winched in a winching apparatus, the apparatus comprising: (a) said capstan for winding the cable to be winched; and (b) a drive motor for driving said capstan, wherein the method comprises: (A) activating said drive motor and setting said drive motor to a non-driving setting; (B) loading said cable on said capstan for haulage by said winching apparatus; and (C) setting said drive motor to a driving setting so as to haul said cable, wherein said non-driving setting comprises a first number of revolutions per second of said drive motor and said driving setting comprises a second higher number of revolutions per second of said drive motor.
 21. A winching apparatus for winching a cable comprising: (a) a winching frame; (b) a capstan for winding the cable to be winched; (c) a drive motor for driving said capstan; and (d) a first mechanical torque limiting mechanism for limiting the maximum torque on a winching load in operation to a first predetermined limit and for maintaining a substantially constant torque under load at said maximum torque. 